JPS5971188A - Magnetic bubble domain detecting device - Google Patents

Abstract

PURPOSE:To obtain a magnetic bubble domain detecting device of high performance by forming the thickness of a soft magnetic thin film that forms a magnetic bubble domain detecting element within the range of 1,000-2,000Angstrom . CONSTITUTION:The relation between the film thickness of a detecting element 9 and the various characteristics when a magnetic bubble having approximate 1.5mum diameter is used in a thin film type detecting device is: when the film thickness of the detecting element is made thicker, the current density becomes smaller, and the efficiency and output becomes lower. The relation between the film thickness and the domain in which magnetic bubble is transferred smoothly under the detecting element is: magnetic bubble can be transferred smoothly under the detecting element in a domain in which the film thickness of the detecting element is less than 2,000-3,000Angstrom , but the magnetic bubble cannot be transferred smoothly in a domain in which the film thickness becomes more than 2,000-3,000Angstrom . In a magnetic bubble domain detecting device, the excellent effect can be obtained by regulating the film thickness of the detecting element 11 to 1,500Angstrom and the diameter of the used magnetic bubble to about 1.5mum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble domain detection device, and particularly to a magnetic bubble domain detection device that has high operational stability, reliability, and high output.

FIG. 1 is a plan view showing the main parts of an example of a magnetic bubble domain detection device. In the figure, 1 is a magnetic bubble transfer path, 2 is a magnetic bubble domain detection element, 3 is a magnetic bubble, 4 is the direction of magnetization M of the magnetic bubble domain detection element 2,
5 is a magnetic bubble expander, 6 is an eraser, 7 a r 7
b is an output terminal that also serves as a terminal for applying the detector current Id; 8 is a basic pattern constituting the expander 5; the magnetic bubble domain detection element 2, the magnetic bubble transfer path 1, and the magnetic bubble expander 5 are made of permalloy or the like; It is made of soft magnetic material. Here, the magnetic bubble domain detection device includes a magnetic bubble transfer path 1, a magnetic puzzle domain detection element 2, a magnetic bubble expander, and an output terminal 7a which also serves as a detector current application terminal.
7b.

In such a configuration, the magnetic bubble 3 is exposed to the rotating magnetic field H
Transfer path 1 and basic pattern 8 are changed by 1 every time r rotates once.
The information is transferred step by step in the direction of the magnetic bubble domain detection element 2, that is, in the direction of arrow P. In the expander 5, the magnetic bubble 3 is expanded into a long and thin string in a direction perpendicular to the traveling direction of the magnetic bubble (direction of arrow P) by the basic batons superimposed in layers. Here, when the magnetic bubble 3 stretched like a string reaches below the magnetic bubble domain detection element 2, the direction 4 of the magnetization M of the magnetic bubble domain detection element 2 is influenced by the stray magnetic field from the magnetic bubble 3. It rotates in response to the Along with this, the magnetic X-pull domain detection element 2
resistance value changes. This resistance change can be measured in advance at terminals 7a and 7.
It is converted into a voltage change by the detector current Id applied between the terminals 7a and 7b, and the voltage change is taken out from the terminals 7a and 7b. Therefore, the output voltage is the magnetic bubble 3 stretched like a string.
The longer the length, the larger it becomes. Installing the magnifying device 5 in the magnetic bubble domain detection device in this way is an extremely effective means, and typical examples of the basic pattern 8 of such a magnifying device are shown in FIGS. 2(a) to (f). Various shapes are known.

Conventionally, magnetic bubble domain devices include the following:alm(a)
As shown in (b), two types of devices were known. That is, 9 is a thin film type detection element. The film thickness of this type of thin film detection element 9 is selected to be approximately in the range of 200A to 400A in order to reduce the demagnetizing field, and because of its thin film thickness, it is called a thin film detection device. On the other hand, Fig. 3 (b
10 shown in ) is a detection element that also serves as a magnifier. In this type of detection element 10, in order to simplify the manufacturing process, the detection element and the transfer path are integrated, and both have a 1% 13
17. '4 is the same and is selected within the range of approximately 4000A to 6000A, so it is called a thick film type detection device.

This type of magnetic bubble domain detection device has the advantage that the transfer path and expander can be fabricated at the same time as the detection element is manufactured, but on the other hand, the film thickness of the detection element is thick, so the demagnetizing field is larger than that of a thin film type detection device, and the electrical The fold is small. Therefore, the performance is inferior to that of a thin film type detection device. In addition, in this type of detection device, the magnification magnification 1 of the magnetic bubble domain is 200 times to 4 times.
The output is amplified by 00 times magnification. The thick film type detection device is mainly used in magnetic bubble storage devices with magnetic bubbles having a diameter of 2 μm to 5 μm, and is the mainstream of current technology.

In recent years, in response to the demand for higher speed and higher density of magnetic bubble storage devices σ, magnetic bubble diameters of 10 μm to 1.5 μm have been developed.

When a magnetic bubble storage device with a capacity of 4 Mb to 16 Mb is targeted, the thick film type detection device and the thin film type detection device have serious defects as explained below. Table 1 below shows representative examples of the characteristics of magnetic bubble domain detection devices with magnetic bubble diameters of 1.0 μm to 1.5 μm.

Table 1 Note that the detection efficiency (V/A) shown in Table 1 above was determined from the relational expression of detector current = 1 to 3 mA.

In the same table, the detection efficiency of the thin film detection device is high, but
The current density flowing through the device is much greater than 106 AAyn2. If this current density exceeds 106) Jcrn, element deterioration will occur due to electromigration, which is undesirable in terms of reliability design.Furthermore, disconnection of the element's conductor pattern due to the application of excessive current is a major problem. Met.

The lack of reliability was a major problem with the thin film detection device. On the other hand, in the thick film type detector, the current density is on the order of 105 A/, n2, and although the reliability is higher than that of the thin film type detector fM, the detection efficiency is lower. Further, in this type of detection device, since the transfer path also serves as the detection element, there is a drawback that the margin for designing the element is extremely narrow. Furthermore, in this detection device, the detection element itself
As shown in Figure 3), since it has a complex geometrical shape, a batan rule for magnetic bubbles with a diameter of 1.5 μm or less, that is, a batan rule of approximately 0.5 μm to 1.0 μm, does not form a batten. is considered extremely difficult. Therefore, it has been difficult to apply the thin film type detection device to magnetic bubbles with a diameter of 1.5 circles or less.

Therefore, in the present invention, the film thickness of the magnetic bubble domain detection element formed of a soft magnetic material is approximately 1000 to 200 mm.
By forming within the range of X, the design margin is wide,
It is an object of the present invention to provide a magnetic bubble domain detection device with excellent operational stability, high reliability, and large output.

Embodiments of the present invention will be described and explained in detail below using the drawings.

Figures 4(:q) and (h) show the results of experiments conducted by the inventors when a magnetic bubble with an approximate diameter of 1.5 μm is used in the thin, vague-shaped detection device shown in Figure 3(a). FIG. 4 is a diagram showing the relationship between the film thickness and various characteristics of the detection element 9;
Figure 4 (a) shows the relationship between the film thickness of the detection element and efficiency and the relationship between the film thickness of the detection element and current density, and Figure 4 (b) shows the relationship between the film thickness of the detection element and the relationship between the magnetic bubble passing under the detection element. This shows the relationship between each area and the area that can be transferred to. That is, in FIG. 4(a), by increasing the film thickness of the detection element, the current density decreases and the efficiency also decreases, as shown by characteristic (2), and the output also decreases. Oh,
Here, the characteristics shown in FIG. 3(a) are theoretical characteristics.

For example, when the film thickness of the detection element was approximately 1000 A or more, the current density became 106 A/crn2 or less. It's a trench.
When the film thickness of the detection element was approximately 2 oooX or more, magnetic bubbles passing under the detection element were trapped by the magnetic poles of the soft magnetic thin film forming the element. Also, transfer became impossible. In other words, as shown in FIG. 6(b), a region A where the film thickness of the detection element is approximately 2000A to 3000A or less.
It has become clear that, although magnetic bubbles can be transferred smoothly under the detection element, magnetic bubbles cannot be transferred smoothly in region B where the film thickness is approximately 2000A~aoooi or more. From the above explanation, by setting the soft magnetic film thickness of the detection element in the range of approximately 1000' to 2000' and making the soft magnetic film thickness of the transfer path approximately 5000x or more, the output voltage is high and the reliability is sufficiently high. This makes the magnetic bubble domain detection device possible.

FIGS. 5(a) to 5(f) are plan configuration diagrams of essential parts showing an embodiment of the magnetic bubble domain detecting device according to the present invention, and since the same symbols as those in the above-mentioned figures represent the same elements, the explanation thereof will be omitted. In the figure, 11 is a detection element according to the present invention,
The film thickness of this detection element 11 is approximately 7-1500A. In this case, the diameter of the magnetic bubble used is approximately 1.5 μm.

As explained above, according to the magnetic bubble domain detection device according to the present invention, the film thickness of the detection element is approximately xooooX~2
By selecting the range of 00ON, extremely excellent effects were obtained in that a magnetic bubble domain detection device with excellent operational stability, high reliability, wide design latitude, and large output could be realized.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the essential parts of an example of a magnetic bubble domain detection device, Figs. 2 (a) to (f) are plan views showing various basic buttons, and Figs. 3 (a) and (b) are thin film Figure 4 is a plan configuration diagram showing an example of a shape detection device and a thick film shape detection device.
a) is a diagram showing the relationship between the film thickness of the detection element and efficiency and the relationship between the film thickness of the detection element and current husbandry when a magnetic bubble with an approximate diameter of 1.5 μm is used, and FIG. 5 μm
Figures 5(a) to 5(f) are diagrams showing the relationship between the film thickness of the detection element and the transfer area of the magnetic bubble when using a magnetic bubble of
1 is a plan view showing an embodiment of a magnetic bubble domain 8-detecting device according to the present invention. 1. Pot/magnetic bubble transfer path, 2. Magnetic bubble domain detection element, 3. Magnetic bubble, 4. Direction of magnetization of magnetic bubble domain detection element 2, 5.
Magnetic bubble expander, 6... eraser, 7 a + 7
b... Output terminal that also serves as detector current application terminal, 8
...Basic button, 9...Sachi Thin film detection element, 10
. . . Thick film type detection element, 11 . . . Detection element according to the present invention. Detection 1j Tsusaki Atsushi (In) (b) 嫂斂-t''3#It! Thick (In) Figure 5

Claims (1)

[Claims] In a magnetic bubble domain detection device comprising at least a magnetic bubble domain detection element that detects the presence or absence of magnetic bubble domains generated in a magnetic thin film having uniaxial magnetic anisotropy, the magnetic bubble domain detection element receives force from a soft magnetic thin film. The thickness of the soft magnetic thin film forming the
A magnetic bubble domain detection device characterized in that the magnetic bubble domain is formed in the range of ~2000 A.